The players and staff at Manchester United are reportedly already "worried" by the prospect of Jose Mourinho becoming the club’s manager due to his "confrontational approach."

According to Chris Wheeler and Neil Ashton of the Daily Mail, while there is no official agreement in place, the former Chelsea chief has told those close to him his move to Old Trafford is a “done deal.” Richard Tanner of the Daily Express reported on Thursday that Mourinho will pick up a yearly salary of £15.5 million, which would surpass that of the next Manchester City boss, Pep Guardiola, and it will make the 53-year-old the best paid manager in the world.

However, despite the Portuguese’s distinguished career and the recent struggles of the role’s current incumbent, Louis van Gaal, it doesn’t seem the squad are unanimously excited by the appointment, per Wheeler and Ashton:

Players and staff alike are said to be concerned about the confrontational approach Mourinho would bring to a stable environment.

They are well aware of the problems that engulfed the former Chelsea boss behind the scenes before his messy departure from Stamford Bridge in December, and do not relish the discord and rows that have become synonymous with the temperamental Mourinho.

There are concerns that Ryan Giggs would not hang around to integrate himself into another new regime, having had to sit alongside David Moyes and Van Gaal while United have slipped into decline.

According to Martin Blackburn of the Sun, the future of Ryan Giggs is a concern for some of the squad. He reported the players are “split” when it comes to Mourinho, with a “fear” festering that the club’s current assistant manager may not have a position in the new regime.

Bleacher Report’s Sam Pilger noted there may be other reasons behind the players’ concern at the Portuguese's possible acquisition, though:

Sam Pilger @sampilger

Of course there's concern in the #MUFC squad about Mourinho's possible arrival, because many of the players realise they will be sold by him

Mourinho does have a reputation for being something of a taskmaster. When the Portuguese takes charge of a club and the team begins picking up results, there’s a mechanical streak to the way the XI functions; they possess quality, intelligence and, most crucially for the former Inter Milan and Real Madrid manager, an unshakeable defensive fortitude.

When momentum is behind the team, affinities between Mourinho and his players begin to flourish. Just look at the emotion that was on show between him and Marco Materazzi after Inter won the UEFA Champions League under his stewardship in 2010:

Mourinho’s postgame antics can alleviate some of the pressure on his players, too, with headline-making quips or controversial views often becoming the main story.

They’re qualities that, for a while, can endear him to players, but in his most recent spell at Chelsea—in which he was sacked earlier in the campaign—they didn’t quite carry the same substance.

That’ll be a worry for the United players. Sure, Mourinho will likely come in, shake things up, fine-tune the team and win a trophy or two. But his managerial career so far is a blueprint for short-term success, not long-term stability.

So it’s a potential appointment the Red Devils need to be careful with. Bleacher Report’s Rob Blanchette tweeted that the summer is the best time to get the new manager in, provided Van Gaal continues to draw the kind of form the Red Devils have showcased in recent matches:

Rob B. @_Rob_B

If team carries on like this, I’m fine with LvG staying til the summer. Then we get Jose with the least amount of fuss. Top 4 not happening.

History dictates that Mourinho—should he finalise a deal to join United—will steer the Red Devils in a particular direction.

He’ll almost certainly bring success, but at Old Trafford—where long-term consistency, adhering to traditions and youth development are also vital—silverware alone is not enough to be deemed a major hit.

That’s why supporters, staff and the players will hold concerns. Mourinho will need to be flexible in his management style should he take the position at Old Trafford and ensure the positives he brings to a football club are not totally offset by the aforementioned deficiencies.